Source code for pycif.plugins.transforms.complex.diagmet.utils.cloud_optical_thickness

import numpy as np




def cloud_optical_thickness(transf, inout_datastore, ddi, mapper):
    """Compute cloud optical thickness for low, medium, and high cloud layers.

    Combines fixed reference optical depths for low/medium/high cloud layers,
    scaled by the ECMWF cloud-cover fraction of each layer, into a broadband
    cloud attenuation factor (``atte``). Only the "read cloud cover fraction"
    option is currently implemented; the liquid/ice-water-path and
    relative-humidity-based options are not yet ported from the original
    ``diagmet.f90``. See :doc:`/documentation/doc-models/chimere/diagmet`
    (section 14) for the full derivation.

    Args:
        transf (Plugin): diagmet transform instance.
        inout_datastore (dict): mutable datastore.
        ddi (datetime): current sub-simulation date.
        mapper (dict): transform mapper.
    """
    # Fixed parameters
    cloh0 = 2.0  # High   clouds optical depth for cl fraction=1
    clom0 = 10.0  # Medium clouds optical depth for cl fraction=1
    clol0 = 50.0  # Low    clouds optical depth for cl fraction=1
    clol2 = 0.025  # Low    clouds optical depth /m for RH=1
    clom2 = 0.010  # Medium clouds optical depth /m for RH=1
    cloh2 = 0.005  # High   clouds optical depth /m for RH=1
    topl = 2500.  # Low cloud top altidue AGL
    topm = 6000.  # Medium cloud top altidue AGL
    toph = 20000.  # High cloud top altidue AGL
    
    # Parameters
    clol = 0  # Low cloud option (0=read cloudiness, 1=Use Liq. Wat., 2=Use RH)
    crhl = 0.85
    clom = 0  # Medium cloud option for attenuation ...
    crhm = 0.95
    cloh = 0  # High cloud option for attenuation ...
    crhh = 0.95
    
    # Inputs
    alti = inout_datastore["outputs"][("meteo", "alti")][ddi]["spec"].values
    clol = inout_datastore["inputs"][("meteo", "clol")][ddi]["spec"].values
    clom = inout_datastore["inputs"][("meteo", "clom")][ddi]["spec"].values
    cloh = inout_datastore["inputs"][("meteo", "cloh")][ddi]["spec"].values
    
    # First determination of levels just below separation altitudes
    levl = np.maximum(0, np.argmin(alti <= topl, axis=1) - 1)
    levm = np.maximum(0, np.argmin(alti <= topm, axis=1) - 1)
    levh = np.maximum(0, np.argmin(alti <= toph, axis=1) - 1)
    
    # missing: XXXX  Determination of liq/ice-water integrated COT

    # Using cloudiness
    # missing: XXX options for using op
    opdh = cloh0 * cloh
    opdm = clom0 * clom
    opdl = clol0 * clol
    
    # missing: option for using relative humidity
    
    # Contribution from all cloud levels
    totopd = opdl + opdm + opdh
    
    inout_datastore["outputs"][("meteo", "atte")][ddi]["spec"] = \
        0. * inout_datastore["inputs"][("meteo", "hght")][ddi]["spec"] \
        + np.exp(-0.11 * totopd ** 0.67)